Pontosphaera decorata
Pontosphaera decorata von Salis, 1994
A Pontosphaera species exhibits uniform interference colours in XPL due to the similar height of the wall and the distal cover over the proximal plate in the plan view. Pontosphaera decorata is characterised by a non-porous, wide rim and a central area with pores typically arranged in three complete concentric cycles, with additional randomly arranged pores in the centre. The apparent angle between inclined extinction lines is 81°, corresponding to an obliquity angle of 9° on the distal side.
Pontosphaera decorata differs from Pontosphaera japonica by having relatively larger pores (0.25 μm, discernible under the microscope) and a lower pore density. In contrast, Pontosphaera japonica has densely packed, minute pores (approximately 0.1 μm) that are barely resolvable in the light microscope.
von Salis, K. 1994. Some fossil “living coccolithophorid” species. Journal of Nannoplankton Research. 16(3): 109-114.
Holotype
Pontosphaera decorata
von Salis, 1994
Early Pliocene
Rio Gurabo, Dominican Republic